An investigation of the effect of the degree of superheat on the economy of a Marsh boiler-feed pump

Illinois Tnstitute

of Technology

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AT 153

Menkin, Jesse Irlis
An investigation of the
effect of the degree of

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AN INVESTIGATION

OF

THE EFFECT OF THE DEGREE OF SUPERHEAT ON THE
ECONOMY OF A MARSH BOILER-FEED PUMP

A THESIS

PRESENTED BY

JESSE IRLIS MENKIN
EDWIN HOWARD STILLMAN

PRESIDENT AND FACULTY

OF

ARMOUR INSTITUTE OF TECHNOLOGY

FOR THE DEGREE OF

BACHELOR OF SCIENCE IN MECHANICAL ENGINEERING

HAVING COMPLETED THE PRESCRIBED COURSE OF STUDY IN

«-LINOlS INSTITUTE OFTECHNOLOGV^^^'^'^^'^^ ENGINEERING
PAUL V. GALVIN LIBRARY MAY 25, 1 909

35 WEST 33RD STREET
CHICAGO, IL 60616

Preface

The sut^ect matter oi thi:: thesis is diviaed
into three laein divisions:

Part I states briefly the ob;iect of t.ese
tests, and includes a complete doscription •*-'
of the apparatur ueed, an explanation of the
operation of the pump and the Fisher hydraulic
governor, and the ^lethod of ca' librating the in-
struments.

Part II includes a description of the meth-
od pursued in the 'erforinance of the tests, a
discussion of the results, the conclusions dravrn,
together v/ith curves, tables and original data.

(a) Tests with Saturated Steam,

(b) Tests 7. ith Superheated ;:5te&m.
Part III is devoted to the bibliogrr.-phy.

?ev7 of the articles herein given, apply direct-
ly to tests v.ith superheated steam, as ver;/
little material on this subject could be found.
The few articles v.hich ap-; ear to be only remote-
ly connected with the subject v/ere included

because tliey ccnt;-'in muca V£l-a.:bl8 informaticn
rel tive tc tests .v-nd oreration of pumps .

The Appendix cont' ins the s mple calcu-
laticns.

The application of surerheated steaifi to
pumps has been very limited. Vtjz little
investigation has been done alonj-; this line and
ccnsequsntly little or not'iiing has been v;rit-
ten en the subject. Lore elaborate tests
had been pi nned, but o\.inj. to practical aiffi-
culties, many of v,hich have be?n overcome, the
scope of the v.ork has been limited.

In tho r reparation of the report, especial
attention has been tiven to ti:e description of
apparatus, and the oreration of the ■ ump and
the hydraulic governor. iilretches and photo-
graphs h;;Ve been ad:,ed v.jiere they api eared to
add clearness. Cnly such t:..bles .nd curves
were prepared ?^s seemed necoer- ry to supply
the desired in:; ori^ation. The r, mple indica-
tor cards shov.n are not intenaed to re-oresent

the averag-e rerfcrmance .f the i^um-n; ti~ey
v.'ers iriclii.'ed in order to expl-- in /acre clear-
ly the cycle of operation in the two cylinders.

Vie v.ish to e:'i~ress our oblirations to
Professor Gt. F, Gebhsrdt, rrofessor of Lecnan-
ical iint'ineering- at A. I. T. for many valuable
sugfesticns. To Lr. )!1. S. ^ibby, instruc-

tor in Jxreriinental inf-ineoring-, A. J. T., we
0'..e our indebtedness for tiie use cf much au2:il-
iary appar-tus. To I-r. J. C. Peebles, instiuc-

tor in Lechanlcal j:;ngineering at A, I. T., we
are indebted for his f^ssisttnce in the calibra-
tion of the t_:ermom9ters, es' ecially ' for the

res/^tafTce.

use of the plfc-tinum ryrometer and the hi;;-h tem-

A

perature standard. s^'ot the celibration curve
of the vonturi meter ..e ov. e our thanl-is to l..essrs.
S. J. Aurelius Tnd J. S. Harvey, A. I. T., 'C9.
To two of our cl.-ssmates, I.e^srs. F. C. ^anzig
and LI. Vanderlrloot , Jr., v'e ex-ress our grati-
tude foi the cheerful assist nee '. hich they ren-
dered during our tests. V/e are also very much

indebted to l^rs . Julia A. Eevexid; e , librarian
at A. I. T., for her kind assistance in miring
up xhat little of the "bibliograrhy we herein
are c ble to ^resent.

Jesse I. Lenlrin.

Edv/in Jl. Stillman.
Chicago, Lay 25, 19C9.

Index
lart I.

Ct:'ect Pa^e 1<

Arrar.£eii:er.t cf jLpparatv.s 1.

The i'tiLip 1,

YalT- Geer g,

T/ater Cylinder 5,

Hydr&ulic Gcverr.cr 6'

P.edr,cin£_ lie t ion 7.

The Suxerheater 7 ,

Conoer-ser 9 .

Piping; 9 ,

C al i 1 1 £ t i c n c f In f 1 1 ta::eri t s 1 C ,
Part II.

Method of Cperaticn IZ .

Tests .ith Saturated Steam 16 .

Discussion, Saturated Huns US.

Tests v/ith Superheated Steam 22 ,

Discn-sion, iiurarheated :\uns 25.

Conclusion 26 <

Part III.

Bihliov-raphy £7..
Appendix

Sample Gslculations

Illixstrrtlong.

Psrt I.

Arrang-GBent of Apparatus 1(a)

Karsh Piimp \vithcut Superheateri' rhcto) lit)

Sectional View of Ilarsh lump 2(a)
Fishor Steam Pump Governor (cross-section) 6(a)

Superheater coils (photo) 7Cb)

Detail of Stea:ii Piping' at lump 8(a)

Harsh Pump and Suporheater (i-hoto) 7(a]

Calihraticn of TernonieterSl photo) 11(a)

Part II .

Sample Cards from ateam Cylinder 18(a)

Sample Cords from V/ater Cylinder 18(b)

Curves of Performance (Saturated Tests) 19(a)

Curves of Performance (Superheated Tests) 24(a)

Final Log 24Cb)

Running Log (Saturated Tests) 24(c)

Running Log (Superheated Tests) 24(d)

Average Data from Indicator Cards 24(e)

Part I.

Apparatus .

Calibration of Instruments

Part I.

Obiect

The -rurrose of these tests was to deter-
mine the effect of tr^e de, roec of turerheat on
the economy of a 2CC-g:llon Larsh toiler-feed
pump.

Apparatus

The general 1' yout of apparatus is shown
in the slretch on T'-B'S 1(a) . '.^ater v.;..s taken
from a reservoir or rump, belo'.. the floor level,
and discharged into v.eighing tanlrs or t:.ru a
venturi meter. Ste, m was supplied to the pump
either from the .i.ain steam line, o, hy-p^^ssed
faru the suve.lieater and t erce tu-iraed into tlie
pump. The exhaust stetm v.ae led into a sur-
face C-naenser end the condensed ctecm v.as pumped
into the '.."eirhing tanks shovvn.

The Pump

The "rumr ±v. shown in the Thotcfrarh on rage

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mofAPP/\mu5

iti PUMP TE5T3

rUTE of nCHNOLO&Y
J£55EI.MENHIN
EDWIN H.6TILLM AN

I Co.)

Ventun Meier

— I 1

Marsh Pump

^weighing Tanks

Superhea ier

^m=rs

AfiRANGEMENTofAPPAmUS
rOff MAf^SH PUMP TESTd

ARMOUR INSTITUTE ol TECHN0L06Y

THESIS JESSEIMENHIN

ISOg H'-l' EDWIN H.STILLMm

jLtlsJtWOX'S: Oi' 'XaiOiUMOJuo«X

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Ub)

1(b), whicli v.as taken before ccnnecticn to the
suTerheater. It is direct acting, having- a
steam cylinder 12" in di meter, a v.ater cjt-i-
inder 7-1/4" in di:. meter, end a maximum stroke
of 12". Its rated capacity is 216 £.2.11ons
per cinute at a sreed of ICO strolres rer minute
v/hen operating v/ith a steam pressure of 8C
rounds rer souc.re inch gauge against a discharge
pressure of 125 pounds per square inch.

The cylinders are separete castings, each
cylinder and base or support forming a unit, tlie
tv;o units being conr.ected as s'.own in figure on
page 2(a). The steam piston is equipred v.ith
two met^i-llic packing rings; the v/ater plunger,
v.ith hydraulic packing. The tv.o are connected
by a br':ss rod l-S/8" in diameter. To the
head of the steam cylinder is att:ched a hcllov?
brass tube ll/l5" in dicmeter, ..hich eerves as
a passage for the .Tteam entering the hollov:
riston. A riortion of the iston rod is hcllov;-

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ed out so that the tube has a sliding- fit.
From the '.ead end of the v.ater plunder an ll/l5"
"br-ss t.- il rod extends thru the cylin.ier head,
and cci^rocts to the reducing laech/ nism. The
air dome ie connected to a stand ■^ipe, this in
turn being' connecteii to a estin:hou£-e air com-
pressor. In tliese tests, hcv.ever, the air
compressor .as not required.

Yslve Gear

Referring to figure on rag-e E(a), stec.m en-
ters the chest O', and ]?«£ ssin^: thru the annular
opening A, formed between the reduced neck of the
vc-lve an., the chest ass is rrojocted a-^ainst
the inner surface of the valve head H, before
escaping into the cylinder by means of port r.
Both the rssEure cf the staam and the impulse
due to its velocity in striking the v^lve head
H, f.rce the valve to tha left in the direction
of the current, thus tending to close or re-

strict the arr^ul;. r steam TassaLe ii. As t:ie
steam ^eaohe.s the cy^inc er, the ^icton it driven
to the right. Steam from the cylinder enter-
ing po^-t C, flo s urv.i rd into the valve cr-est and
exerts a counter ' ressure on tue left side of the
Vcilve head h, tenainp- to drive it to th-) right -
a movement vhich ■. culd ^Ive g-.i eater port open-
ing to the entering chest frcin the chest C.
Tie v.lve, therefore, ic al'.ays balanced, and
occupies s pcj-ition de-ending uron the relative
intensity of the tvo forces v.hich tend to move
it in oppc: jte direction — .Adinissicn Steam —
vv ich tends to clo:-e it, c.nd Cylinder Steam.
v?hich tends, to o--cn it v.ider. Ihis ccnttitutes
the ste&m governing eleiiient.

The steam piston conirist, as sho^/n, of a
spool form, each head beini-'; proviced i/.ith a
metf^lic packing ring, the interior s-^ace R
forming b reservoir for live Ete<-m v.hich is
supplied from the upper chamber of the steam

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chest by -nrssage li to the cylinder cap S,
thence by tube L and the hcllcv, piston V.
The vrestvixe cf thie steaw is used only for
"tripvin.c;" or reversing the valve by admit-
ting ste&m alt ernf-tely ag-ainst tlie outer sur-
fr.ces of the vflve heads H thru the ccnr.ecting
passages C,C, nef-;r each end of the cj^iinder.
The t-iprets T ire ueed for moving the velve
by h&nd in case it fi.llE to start automatically.

Water Cylinder

The water cylinder, r_ ge E(a), is divided
into two com-'^ertments A and B, heea tnd crank
ends. As the y lunger mcves to the left, water
is drav.n thru the disc valves A, A, into the
Lead end: at the stine time v.ater iE fciced from
the crank end thru tlie valves c, c into Chamber
C, The mcvenent of the yliinger to the right
delivers the head: end chrrge and refills the
cran]-: end.

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The Kydravilic Coyernor

The sl:etch, p£.ge 6(a) shov.-s the i^'isher
hydraulic rcvernor. The syring S tends to
hold the c cuhle -"balanced v&lve Y off its se&t
thus allov,ing- adralssion steam at full fxes'^uie .
The presEue of the v.ater in the delivery pipe,
trj.nEmltted thru pipe ^ acts on the viston tend-
ing to cvercoEie the resistf.nce of tlie s- ling: and
close the valve. Hence it is seen that with
£:iven steam end discharge pressure, the vrlve
v.ill essume some b:-lenced position, snci that
any rise or fall in deliv-ry pressure v.ill
tend to close or open the valve respectively.
If a lov.er delivery head is desired, the re-
sistance of the srring can he adjusted by moans
of hand v.heel K end lock \7heel L, so that the
valve v.ill assume a -^oriticn of rest ^.ith a
lov.er water pressure at A. The piston red
R is pinned to the sleeve T and the valve stem
B which is ri^-idly attached to wheel I, is
screv.ed into this sleeve, thereby altering tiie

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FISHER
STEAM PUMP GOVERNOR

AHJMtorm

tension of the spring.

Red-acing Lxticn

The reducing mechenism is shov.Ti in the
rhctogra-ph on rage 71 a). To the tiil rod
is attached a pE.ntogr- ph :.hich trensmits mo-
tion to a 5/8" steel rod mounted in suitable
bearings, so that its motion is exactly parallel
to that of the riston red. Llounted on this rod
at points equidistant from the indicate rs are
tv;c aluKinuri "finr^ers" to vhich are attached
indic&tor cords made ecual in length and as
short as possible. Tliu^: 'octh indicators sxe
actuated by the ^tme mechanism v.itLcut any aprre-
ciable error due to unequal stretch of the cords
due to a difference in their len.ths.

The Superheater

The superheater consists of three concen-
tric coils of S/4" steel pipe, 10", 2C" , and 28"

-7-

7 (c,)

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m

F

7(tJ

in diameter, each of lC-l/2 turns. The
three ceils are welded together ;::al"ing: 16C'
of contir.uous ripe. Steem enters at the
top, passes dcv.nward in the cuter coil, ther.ce
upvard thru the central coil, dov/nv;ard thru the
innermost ceil anc out 't the bottom, to the
puiiip. The detail of the steam piping show-
in£- the connections to the superheater is sr.ovni
on page g, a) . The spaces het'^-een the turns
in the coils are partially filled .ith strips
of asbestos ..hich serve to deflect the l.eated
£Tses and afford a uniform distribution of heat*
The coils are turroimded by tv.o sheet iron shells,
5C" and 56" in diameter. The interveing tipace
is filled vith cinders to vithin 1" of the top,
to rrevent radiation. At this point, around
the circumference of the inner shell as a
series of I/E" holes vhich allov/ the rroducts
of combustion to escape betveen the shells to
the stack at top of cover. The coils ere mount-
ed on a three-legf^ed circular base about E4" in
height. Heat is suprlied by 4 - 4C cubic foot

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S fa)

ll.il. «i ?UU

gas burners feeding :rom a 4" x 3' reservoir
ccnrjccted to tv.o s/5" gas Uiains.

Cone-enser

The condenser is a '..'ainrirht surfi.ce con-
denser conristin: of 115 tubes 5/8" e:'.ternal,
l/£" int /;rnf-l dianieter snd 54.5" in lengtii, nav-
ing a steam aurface of 84 scu: re feet and a
v/ater surf ce of 67.5 p.nu&re feet. ix 1/2"
C":"ening permits venting to the atiiio sphere v.hen
condensing at atirc spheric preeeure. A email
Harsh pump delivers the condensed eteen; to the
weighing tanks.

Piping

The main ste; ni pi": e is l-l/2" in dic.Hieter.
The by~pass to the surerhoater is l-l/£" t^nd is
connected to the suTerhester by reducing ells.
The exxiaust steam pipe is 2" in diameter. The
s.ueticn pipe is 4" in diameter end is fitted t ith

_<j_

a gate Vc Ive snc a t'l.erracmeter cup for de-
teruiining tho temreratuie of the v.ater.

The discharge rire is 4" at the piimp and
reduces to 2" et the tanks. Tc the right of
the stand lipe — phctocraph, pa^^e 7(a) ■- a
l/£" piT-e from the dischar£,e line tr.'-.nsmits
the v.ater pressure tc ore rate the g-cvernor.
The £tand pipe is 8" in diameter and 8' hirh.
A 1/E" pi-re connects it and tho air doi.:e of
the punp, to a '.Vestinf house air cocipressure so
that any desired pressure c; n he obtained.
During these tests the com-resscr v.ts not used.

Calihration of Instruments

The thermometers used were ill Fahrenhoit
and v.ere calibrated agf inet to 8C0° nitrogen
bcrosilicate st.rnd&rd. This sttndc-. rd ..as in
turn calihr&tec with a plc^tinum resistance py-
rometer equipped with a V«"hipple temperature in-
dicetor — fl93C — m^de by the Cambridge Scien-

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tj'fic Instrument CoEp-^::ny. The nitrogen
Et&ndr rd v.as fcuno to be correct. The thor-
mometers ". ere inserted in e Tortable blsst
furnace — see rhctorrBph rarelKa) — which
was heeted by a g'as flame.

The venturi meter had been previously cal-
ibrated by I^essrs. Aurelius tnd Harvey, A. I.T.,
'09, v.ho plotted £ Cc librf tion curve . iiich v.as
used in tr.ese tests — f:ee tresis of S. J.
Aurelius f.nd J. S. Harvey — "Coinpf risen of
Ii;fflux Coefficients for various shares end siLes
of ilozzles" — .

The pressure grug-es v.'ere calibrated v.ith a
Crosby dead-T.eight tester; the s terra gauge v;as
found to read 5 rounds too high; the discharge
gauge v.as correct. ILe vacuum g- ^i; e v,as cali-
'orated . ith a '.heeler surface condenser and read
correctly.

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Ilicv)

The Ta"bor indicator s-^rini-t: v/ere cali-
brated in the Ltet-in line sgainst a calibrated
steaip £ u; e . Calibration of the srrintie v ere
wcde "be fere the stty rated runs, and arain he-
fore the FXir-3 rheated runs. The true sc les
are indic?:ted on the lo«? sheets.

-IE-

^art II.
Lethod.

Tests '..ith batrtrated Steam.
Sests 'with SuDerheated Steam,

Part II.

L'ethod

The freneral method v-as to send saturated
steam thru the surerhoater v/here it was rj-ised
to the desired temperature, thence turned into
the puiap. The temperature of the saturated
steam v.-as deterinined from the -auge pressure
at the throttle; the temperature of su^or -
heated steam was determined by me ns of a ther-
mometer in steam ripe just before entrance to
the gcA-ernor — see sketch, page9(aj— .

A series of rreliniinary tests \;ere made
v.ith saturated steam during vhich great diffi-
culty v/as experienced in tc:l:ing indicator
cards due to e;:cessive pounding in the \.ater
cylinder. 3speci-lly v;as this tiue at high
rates of seed. It was also found that the
weighing tanl'S v/ere of Insiifficiont capacity
to handle ! he quantity of v;ater discharged.

-IS-

The slip v;as also excessive being in the neigh-
borhood of lu :^er cent. It vas therefore
deemed adviscble to overhaul the •^ninp. Ac-
cordingly, it was disnantled, the valves ex-
amined, and ne.' met llic racking rings were
nir.de for it. A nev s rin, ring of l/8"
steel v;as iri?:-de for t.ie v/ater ^^lunger ind the
hydraulic pacl:in£ v,as renewed . To reduce
the ^-ounaing, a l/4" valve wrs pl-rced in the
suction line. The ouantitj'- of air thus
dravvTi in ..ith the v.t.ter was reduced to a min-
imum CO that the consequent decrease in capac-
ity was negligible. Cwin.i: to the poor con-
dition of the pump the reeult^ of these tests
were not kept.

It was origin^ 11:7 planned to mohe a series
of performance tests at varying spseds v;ith
S-tur:ted steara, t.nd a series of comparative
tests at varying speeds with varying def_rees
of superheat. After completing the first

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superheated tests it v.ts fcrmd that time .ould
not ;^-erii:it carrying out the cririncl rl n.
It required from 2-l/2 to 5 hours to --et the
temperature of the superheated st%an constant.
It v/as, therefore, decided to make the tests
v/ith superheated steam at constant speed, vary-
ine: only in the decrees of su-^erheat.

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Tests ith oaturated Stoam

Tliese tosts v/ero of 30 minutes dura-
tion. Observations v.ere t^lren at int rvals
of 10 minutes, of stG;;ii;i, e:Ca .ust and dii^charge
[pressures, temperatures in the calorimeter,
suction vater &nd room. The steam -rrosKure

was determined hy moans of a steam gsup:e, the
exhaust pressure v/as measured hy a vacuum
eauge, and the discJhar{:e pressure by a pres-
sure g's.ure iiicunted in the disch r~e pipe near
the T-.ump. The eteam supply and speed v;ere
r-^^rulated by ir.eans of the Fisher gcvei-nor; the
discharge pressure v.as m:.intained constant
at 60 pounds per square inch by i.ieanG of a
v^-lve in the dischar e line. The suction

head \vas me-.sured v;ith a rule at the start
and finish of each run, the average being used
in the calculations. The quality of stecm

was determined v.ith a throttling c" lorimeter ;
the temperature of the water with a thermometer

-16-

inserted in s suit'- ble oil cup plpced in
the sucfeion pipe close to the ptunp. The
exliaust steam v.as diEchar^ed into a v.ain-
right Gurfcce condenser condonsinr at at-
mosT^herio -pressure. The steam condensed
was pninped into veifhing tanl:s and weighed
once during each run. ilo ; ccount vit-s ta-
ken of the tem-^'orature nor the weight of
cooling v.ater UL-ed in txie condenser.

The water pumTed was delivered to tanlrs
and weighed. '..hen the s-eed exceeded 40
strokes per minute, it was found impractioable
to V; eigh the water, so thf:-t the venturi Lieter
was used. '..hen the capacity bec.s-ue too
great for the mercury colunn to hfi.nu.le, a
portion of the v/ater from the pump was by-
passed to the weighing tanks; the total v;ater
pumped, 'being the sxm of v.eighed and metered
water.

-17-

Indic^^-tor c; rds v;ere t&Iren siiaultv-necus-
ly froLi both cylinders every ten lainutes, in-
dividual G-:rds being taken for liead and crant
ends, 18(a) , 10i b) .

The speed of the purnp was found by means
of a stroke count or attached to t'le tail rod,
which registered double strohes. This was
read at the start and finish of ecch run.

The ratio of reduction v.as determined by
means of a ^- ncil, mounted on the tail rod,
which traced a line en a sheet of r.^-or \.hile
r.nother line v;as simultaneously drr..wn by the
indicator ■ encil. The ratio of the lenrth of
the "iston stroke to the length of the line
drav/n on the indicator card , on the s?:me stroke ,
is the re tip of reduction. This ratio v.as
determined on the crank end stroke of the v/a-
ter c2/.:inder. A g'reat m-ny determinations
were made »t various speeds. Tliere was oon-

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Head End dteattiCard
3teain at 71" Superheat

Zl 43 strokes per Minute
Scale of Spring 6Z.lh^-l"

16 CoJ)

Hcni End Water Card
Steam at JZ" ^Superheat
Area-2.04''" Letigih^Zd?"
2/.4J Jtro/re3 per Minute

macHAr^e cnUa Diaehint Beams

5jLi/on Be fins

SuctiOi) £nds

CranK End Water Card
3 tea mat 7Z° Superheat

Area^Z.OO* Letriffh-W
ZIA3 jfrokeo per Minute
Scale ofSprih^ dJ.^tl"

Discharge Begins

Discha r^e £nds

Suction Bagips

18 ft)

siderable variation, but it followed no
general lav/. The avera£,e of these v/as
ta]:en as the ■prcbahle true ratio. T'.;is
variation is prob'-.TDl;; due to inj-'-erfections
in the reducinp- mction or to a sli£,ht "bend-
ing of some of itc linlrs.

Discussion

The results of these tests are shov/n
graphically by the curves on pi-£e I9[a)..
T.'ith the exce-: tion of the tost at 54 strolres
T'or minute, the points fall ( uite miifcrmly
on the curves. The error in this run is
paohahly due to the inv-c curacy of the ven-
turi meter, at Ic heads, this being the
first run in -..hich the meter v;as used.

The curves show that the capacity ind
horse pov/er increase directly v.ith the s^eed,

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5 «

0 ^

'otJ:^^'

t i!

-! in

a. ,[:

^ <o

e uj

^ 't

t^

o 1 u- u

e. ? >-

"^ I

6 ^ H

10 f-

OiJmO \iVA-rtK PuMPtc

ZO 30 40 So 60

SirtGLe :

/9 {a.)

The efficiency ''nd duty increase v;ith the

s--eed, reaching- a aaxiiatun at ^bout ICC strokes

per minute. The general trenicf the curves

indic<^te tiiat, if the Tump cculd be o''--erated

at a STeed exceedln- ICO strokes per iiiinute,

there . ould be no increase in officioncj'' or

economy. It is also evident that tlie econ-

cnmj' increases greatly with the s'-eed. iTrom

the vvater r te curve, the steam consuinption at

4 strokes Tor minute is 284 pounds per I. h. I,

hour, at EC strokes it h.-.s already decreased

too
to S64, .,hile at 40 strokes it is as low as

i*#. i*h-om there on, the decrease is com-

paratively slight reaching a minimum of i^

pounds at ICC strokes per minute.

The B. T. U. curve shov;s e:c- ctly the
same characteristics. At the slov/est
speed — 4 strokes rer minute ~ IBCCC B. T.
U. are supplied i->er delivered horse po er
per minute. At 2C strokes t/.is has already

-£C-

decreased to 44CC, and at 4C strokes only

2CCC B. T. U. are required. At 100 strokes

the heat CGnsuia-~tion is only 24C0 B. T. U.

Thus it is seen that an increase of 20 rer

cent in speed at lov>- velocities increases the

economy ( 18CC-440C) _ 75.5 ^'^r cent,
1800

In conclusion, \.e may say that v.hen ©".'der-
ating v.'ith saturated steam:

1. The ninimuin efficient sreed is
40 strokes for minute,

2. That the economy increases ".vith
the s-eed.

3. That the caracity, duty, horse
]^ov.er , and ef ficio::cy increase
v.ith the speed,

4. That the ma.:ciLium efficiency, au-
ty and c Tiacity are oht-vir.ed at
the rated speed of 100 strokes
per minute,

-">! —

Tests '..itii SuTerheated Steam.

At tiie ccmi_cncei2ent of tiiese tests it v.as
found th&t the dror in rrsssuro thru the super-
heater was nearly 5C per cent of the ua:K:imuia
steam rressure attain^hle . ith saturated tteam.
In the former tests a maiK^^imura steam pressure,
at the higher speed,?, of 80 omids ;c.uge could
be obtained; \. ith steam thru the su;^erheater ,
at lov. degrees of superheat, the steam pressure
dropped to 45 ;'0unds an.- the maximum attainable
speed v.'is 36 strokes per minrLte. The s;'-eed
throughout the.'^e tests was maintained approx-
imately const- nt, at about 22 strokes per min-
ute. The discharge pressure v.as ":ept con; tt.nt
at 6C pounds per square inch. The tempera-
ture of the superheated steam v.as 1 ept as
nearly constant as possible throughout the run.

At lo'..' decrees of suT^erheat not much diffi-
culty v,as encountered in keeping the de,~ree of
su-erheat constant throu^ehout the run. ^t

-22-

high decrees of superheat there v.as a fluctu-
ation of 5 or u derroes, nd noro tine v/as re-
quired to attain even ti:is cor.Jltion, The
adfustment of the steam governor h-^d to he
mc--de \ ith mere c^re, as it "became much mors
sensitive as the tem-erature range increased.
The discharge valve likev.ise had to he watched
m.re carefully as there was considorahle fluctu-
ation in the rressure.

Temperatures of superheated steam "lere
read every E minutes, the cveraje v^.lue heing
recorded for the run. Cbservations of the
steam and discharge pressures, suction head,
and temperature of water were recorded every
10 minutes. The speed counter was read at
the start and finish, individual indicator ce.rds
were tfiken, as in the tests with saturated steam.

Discussion

From the results oct' ined, the curves, pa^^e

-ES-

;2-fi a) v/ere dravn. The delivored or Tumr
horr.e pov/er is seen to have a fj-eneral de-
crei.se durinr- the series of su-'crheated runs.
This, hov;eVGr, cannot be attributed to tl:o
increase of superheat, as tlie aeliverea horse
pov er is e lunction or speea ox '-ump, length
of stroke, and delivery head. Lut it is rrcb-
ablj)- due tc tlie inability to l:eep the speed for
the various runs exactly constant. The high
and lo'.v roints seen tc cor:.'esrond '..ith the
high and low speeds res ectively. There is
lij:ev;ise a ccnstsnt decrease in the ji.ech: nical
efficiency "v.ith increase in the degree of super-
heat. This is probably on account of incresed
friction due to the unequal ex^.-nsion of the
piston and cylinder v."; lis. To obviate this,
the cylinder ehould be l':g£ed to prevent so
great a difference of tenijB rature botv/en the
inner and outer walls. The v.ater rate and heat
supplied, decrease quite rapidly v.ith an in-
crease of superheat. The duty and thermodjrnamic

-24-

2 4 Co.}

AjLiMn-xna.

3^ 'h)

dJttHotm

MAR5H Steam Pump

B.T. U. Pen I.H.R/H

SUPPLfELD . P<^nD.H.P.M

THLRn. E.QUIV. ofWorkDohe./!

■liiiiiii'iy-^'-'^"— TaMta

^^^mEafflg3Effl^BBmilBB3ai'»"'"''»'MMiLiiiJjjjiLiJ.w»iii!i!^

Z^(i>)

AHMoona

RuMHiMG Log

TtftT OF

Marsh Stciam Pump.

AT

Varying Splelos

WITH

Saturated Stelam

IMDICATORS ^ATER TaBOR 8239 SPG.

Steam Tabor fez-ife^SPG.

Apr. 19. 1909

NoorRuN

SuCTiOM

H£AO IMS. M..6[ zs [,2.n| 25

Stm.Lbs. ^^ '^*'

.S-I2.S8 2 3 s.sa a4.s I4.J8 2 3.8 U.47 2

i4.J-|3 28l 23.»L.»6|24.s|5:oal2S.8 Ln 1 2-i.S I7.11I 2-^

7; 208 27a 333 38+ I '^'♦S

Stroke

VE.MTURI

meter

IBB^^gBlimiBBBgBgBaBaBE3BBBB

miuidl

tWIBEHll

6.44 9.3 19.35 23.ia I 1 9. 1 1

RursMiiNG Log

TE.ST OF

Marsh Steam Purop

AT

COM*>TANT SpEE.D

WITH

SUPEIRHELATELD StLAM

Indicators ^ater T-abor
5TEAn Tasor

Kjjtti^gi ebEEESI kSeHSj t-fifUM Bsaaoi b^^^

MB

. I9M3I \s.oo\z9.y \t:et,\ 29. \

'3 34- I !S» jrj Vj37.^ly.oi- J( I l*\lf.r\ If,] 31. I ;3

3^«^ 4:»o J J SJ Jy. If:i4- J2. to Z0.S-1 tfc J/. ^3

EBlMaEffilEEiyffiKaigaBiaBngggagiiBHB^BBigzM

&0 I 60 6<» ^e

60 I &0

JPHBIBBBi

70 I 7«>

*« 64- U*^ \ (.3

60 \ \ SO

~~B9 BSBZi BBKZa BBSBH tSasa EZSBB BSBa ISQBJI ESDBS

5tm'!'l86. '^^ '^^ »J^ /3fl. 1,7 \ 9S. 9Z 83.

Punpto" 'o^T>- \iofoy faai \/o8/^\ 100S3 9073. ,04^4^ \ <)oio.

'3. |/a?i|5^9/V |g:fij-»-7fl.|ro°|907J |/ a*|t9ll- I-? "j) <7'-

ISSSEH33jCS!I

HflLgJ SBmxi PgflHHB IBHBtH HWF^CT BBBBTWi IHWngTH i

|BARoriW/5l2 9.2 4 I 29.4 I Z?> lz?.9S I Z*.4- I 2«t98 | 2f.y I Z<^.A-

. DOUBLE.

^-;» /'o',)

AHMOtJB

AVERAGE DATA

INDICAToH""cARD5
TE5TofMAR5H^TEAMPUMP

»l=»H»»,-^J^«'^^wirirJsll^LeI33an

NUMBER of RUN / ?\

STROKES PER MINUTE \\3.96 \/S.6J\Z9.20\4l.73 \SJ.9J \70.30 I 8fc.73]/oaIIl

QUAUJy of STEI\M (%) m.i4\98.0S [9 7. 7 J \^8.I0 \978S\9e.Z0\9S.lb 198 70 \

I \AREA ohCARD (Sq.in) II /.e/ I /./6 ±^99 \ hzo \/.zf \/.36 \ 1.4.9 \i.si I

jjiigMi^^^aiga|Bza^giHaHaBa

LEN&TH ofSTROICE (P

/IREA ofC/^RD
C«/«N/f LEN&TH ofC/»ffP

LEN&TH -/STROKE

/»REAofC/IRO

HE/>D t-EN&TH .f CARD
LEN&TH o^5Tff0h'£

LAREA*/ CARD

jCffANKl LENGTH ofg/lRD

LEN6TH ofSTROKE

\2.78\3.03 \2.9b 2.9J 3.i7/ IJ./Z \3.IU

imEamnrnm^i'iiiMMAWcmwanmrn

\L97\Z.I5 \Z.I4 \Z.II \Z.Z3 \Z.S-I \ZC7 \2.83

\ZA3 \Z.9Z 1 2.8* \2.67 \2.94 \j.08 \3./S \3./i,

.61 3 \ .903\ .68S\ 1

\l.79 \2.li, \Z.I7 \Z.lO \Z.ZS- \z.sj Iz.i^f \2.8S

\Z.^I \Z.9Z \Z.95 \Z.86 \ 2.9 7 \3.0S \j./J- Is./f

NUMBER of RUN

STROKES PER MINUTE

DEC-REE of SUPERHEAT

\ AREA of CARD

HEAD LEN&TH tf CARO

< 5 I LENGTH ./stroke:

/JREfl cf CARD

• \CFANK\LeH6rH ofCARD

LEMGTK ct STROKE

\AR£A of CARD

,r- \HEAD LENGTH of CARD

LENGTH ,fSTROK

AREA of CARD

■■ |CR/>NK[LEMGTH ef STROKE

I I LENGTH ef STROKE

kJijJdtiiH^idfm^nwtzi

izz.se\zz.i7\zi.4j\z!r.07 \z1.93 Izo.solzz.mznJl

_0___33^_72^90J_lZ9jd_![8j^lZ0^24±l_
JM_U^3_JJ;4^JJ8_U^_l2a±UZ^_/^093_
2.9/ 1.9S Z.9S ^.83 Z9Z 2.94S 2.8*3 2.753

II tm-.9U I -9/1 I .614\ .904\ .969\ .ee^l .flAoi

\\I.I3\1.0S \I.I7 \U0. \I.ID l/./V M.et \/«9 I

\\Z-9I \Z.93 \Z.93 \Z.84 \Z.9t \Z9c^^\Z.e7 Iz.B^a

^snmEaimLEkmmMmnAw^kmmzmKwrnkA

Z.OB Z.ll p.04 \z.oo \Z.io \z.07 \2.0A \/.9<fJ
Z.87Z Z.9I Z.90S Z.7J- 2.693 2.6 S z.ei3 2.748

iRHimi;iMmiif*Mmii'amrn!nmnTmwm-n?\m=ai\i

2,0j_^gg 2.04- 198 2.0 3 Z.o03\z.O3 \/.9ej\
Z.8i Z9Z 2.895 2.74 Z.073 Z.&Ai Z837 \Z.7Ss\

\Se3\ .9ci\ .995\ .esz\ .867] .8781 -87^1 .0So\

2 ^ ( e;

AJ.-UJ ■' • ■..' li

efficiency inciep-se almost directly vita the
degree of superheat.

Thst f reater econoff.y is obtitined with an

increese in the decree of sui^'erheat, iLey be

seen f^om the follov.ing table. 5trrtin£- v.ith

saturated steam, or zero derrees of superheat,

the ;:ain in xer cont of L.T.U. £u;^rlied ot zero

decrees superheat is — see curve ij.T.U, per 13. H.

E. per ninute — , noted in following table:

Ser-ree SufB rheat Gain in Per Cent

75 11 ( 56CC-51CC)- .n

SGCC
100 14 ---( S6CG-51CC) - .14,

S6C0
150 21 (S6CC-£85C) _ £i

56CC
EOO Z4 ---[ZGCC-275C) _ .24.

36CC
E40 SS - — (26CC-24CC) _ .55.

36CC

The water rate at 0° it £CC pounds per I. H.
i, hour. Ihe decrease in the '.vy.ter r;,te can be
seen below:

Jea-ree Superheat Iiry Steam per I.K.I-. Hr.

C ECC.

75 159.

ICC 148.

15C 150.

2CC 118.

240 lie.

-E5-

Conclusion

The results of tiiis test v.culd inaic.jte that
with the rump operating at constant s^eed,

1. The economy is a direct fimcticn of the
degree of superheat.

2. That v.ith the rump in its present condition
the mechanic 1 efficiency decreases . ith an in-
crease in the do:;-ree of sur-rhet.

3. That the thermodynamic efficiency increases
v.ith the degree of su-^erheat.

From this it dees not necessarily follov. that
the economy of all pumps, nor even this pump, in
actual use as a boiler feed, v culd be inc:^ eased by
the use of superheated steam, as much v/culd depend
upon the method employed in su-'-erheating the steam.
V.hether or not the economy v.culd be increased v;hen
jJhe cost of ;' reducing the siiperheat is considored,
is beyond the scope of this ti.esis. This .ill
depend entirel;^ upon existing conaiticns c;nd is a
problem that must be left to the c^^ rating en&ineer
to decide.

Resrect fully submitted.

Kay 25, 19 C9.

Part III.
Bitliogrerliy*

Marsh I oiler Foed iTzinp.
Engineering.
6C:946

Pumping Tests \.ith the Sujerheated Lteam
U, S, Engineer

S7:140 Jno. 1, 'CC.

Pioinpinr iiJngine Test . ith Superheated Steam.
Engineering.

70:221 ]5ec.l4,'CC.

Pumping -engine v.ith Superheated Steam.
Sng. Heccrd

41:475 i:ay 19, 'CC.

»

PxuLping iiingine Tests v.ith Superheated Steam
Pov.er

2C:£3 Dec. 'CC.

Conditions of Lax. iruxn-ing jingine 3fficiency.
3ng. i:ev;s

44:21E Sept.E7/CC,

Zl

Eoiler Feed-Ptunp Efficiency
iingr. Londcn

8S:152 Feb. 5, '97.

Feed-pump Sfficiencies.
Sleet. V. crld.

56:455 Se-t. 7, 'CI,

CoinpErative Steam Pump Tests with Satursited Steam.
Sng. llev;s

51:3C1 Mar. 51/C4.

Tests of Small Steam Pump for Poiler Foed.
Sng. r-.eccrd

44:E33 Sept. 7, 'CI.

Consumrtion of Steam Puinps.

iJH. Log. Lech. 'Ln^r.
17:145 - 95

Determining the Caj^acrity of a lov.er Pvunp.
xov>er

Cct. 27, '99.

^e

Pules S; Fornml' s for Steam riun-^s
jin£ r . — U . £ . L. -
56:49

Action of lUTips.

iJng'. iviag.

25:123

Some lump Problems.
Am. i-acn.
22 :7V'

l^cli. 1,'99

Arr,

Feu. 2i,'y9

(Jom]"t:rative Value ci ^iixerent Arx?'ngenont of
Air cliKmbers on iui.irs.
Pov.er

21:11 Jan. »C1,

Setting the Valves on St asm iUiiirs,
lov;er

17:4 Jan.

7 Fet.

7 L'y.)189 7,

7 Jne .

9 ilov.

a9

Po'..er 1.

Pov;er

18:19 Dec. 1898.

GelDhtrdt — Steam Power Plant iln ineering,
p. 468

p. 475

Rogers — rumps S: Hydraulics.

J. C. Library 5£1.6

Q5CC

Economy Test of Peed-Iurps.
linr-. — Lone en ~

87:4C Jan. 12, '99

:118 Feb. S,'99

:S45 Apr. 7, '00

3<^'

Apr end jy

Calculations

The follov;in£ series of c lcul--tions are
for run nunbor 1 of the series of superheated
tests ( only those hcinp- shov.Ti v.hich were deem-
ed necessary for explanation) and are rrosented
to show the i::ethods used in securin: the results
which aprear on the y'intl Log of rage 2-41)).
V/ith the exception of the determ 'nation of the
quality of eterm at admission, thcS . coi.irutations
show the methods for securing the results of
our c.uturated runs also. Hence, the c^lcu-
laticns for the cuc:lity of steam of the first
saturated run are included in the follov/ing.
In all esses, the dcta used, consists of the
average corrected ohsei v^tions of the test un-
der consideration. Peahody' s tahles were uced
for heet vrlues.

Item 5. Single stroke per minute.

Speed ccunter reading at start, 3857.5
ST^eed ccunter readinr at finish, 419C.

(419C-g857.5) X 2 = L£.1V sinrle stroL-es
30
per lain.

Item 4. Lenrth of strolre

Av. lar- th of lioad end cards of water

cyl. = 2.91"

291 X ^^-^^ - 8.99' .

12
Av. len-th. of eranl: end c-rds of v.c.ter

cyl. = 2.92"

2.92 X ^-^i^ = '^^Cl'

(9C1+ 899) -T 2 = 9CC' .
3.7C4 = stroke ratio)

Item 5. larometer

B'crometer read 29. 4C" Kg.

2940 X .491 = 4.44 l^bs. rer so. in.

Item 12. Temperature of saturated steam se-
cured from ste; m table.

Item 1* Degrees burerheat.
Ifem 12 — Item 12

Item 18. Liechj^rge j.ressu:,e (feet cf v.ater)

60 ^ 1^4 _ 138.7
62.51 '

(62. SI = denL:ity of vt^ter at 7C®^

Item 25. Steam r-^:* !• H« ^« licur
5C6 4 1.584 = .01484

Item 51. Specific Heat of superheater steam
secured from curves on -^e-ge 157 in
ProfesEor uebhardt's "Stes.m i'o'.ver
I lent iiingineering."

Item 55. Cu. Ft. of v.ater punped

1C5C7 _

62.51 " 165.5

Item 54. Gallons of v.ater puiiiped
165.5 z 1728 - 12S3
251

Item 4C. Plunger diepiacement per hr. (cu.ft
A X L X U X 6C

A = Av. piston area in sc . ft.
L = Lenrth of stroke in ft.

U = Sinrle Etrol:es f-er ciin.

i^^25 s 9 X ££.17 X 6C = S35.
144

Iterc_41.

Per Cent slip

Item 40 - Item S6
Item 4C

S35-3S1 - 4 _ 1.195:

io

335 3S5

Item 46. I. H. i-. (steam)
PLiJI

33CC0

( .911z:9C5)( 115. 1^-111.6) ££.17

£3.3 X 3.704 £ £ -1£84

S3CCC X 1£ X 144

Item 47. I. H, P. (water)

59,6 X .9 X4035 x££.17 = 1.450
33CCC X 144

Item 48. D. H. P.

14C.8 X £0614., 1.458.
53000 X 60

Item 49. i<'riction bet'.een cylinders l,.).

I. E. ^. (steam) -I. H. P. ('..ater) -
1 , .:. P. ( steam)

1.584 - 1.458 _ 7 05
i.5B4

Item 50. Heoh. 3ff. = icO — 795 = 9£.05/u.

Item 51. Ji. T. I'. Surplied per hour
SC6 (H4Cp S - qg)
306 [1167+1 .58) (5^.) - 2114 52]
SC6 11C07.) = 5C8,CC0.

Item 52. B. T. U. per i. H. i- . min.

308, COO * 60 4-1.534 = 5240.

Item 55. Duty per million E. T. U.

140.8 X 2C614. icOCCCC = 9,4lC,CCC ft. l"bs,
308,000

Item 56. Termal 2qulv, cf v.orl: done rer hour.
1.468 X 2545 = 5740

Item 57. lEhermodynamic Efficiency.

5'?'40 X ICO = 1.213^^
30 8, ceo -L-'=-L«^/»

Quality of ate am
s:i ri+qi = rgtCp ( ts - t2)
( Subscripts 1 correspond to conditions
in tlie stesm pi~e snd subscripts £, to
those in the calorimeter.)

p. - 46. 9S Its. Abs.

tg - terarorature cf suTGrkeated steam

at atmospheric rressure of 14.45 lbs.

C-p = s-'-ecific heat of su-peilie- ted steum

in calorimeter. Its vr^^lue v;es secured

from curves on p^-Ce 137 of Professor

uebhardt's "Ste::m lower Pl'.nt iin.rineerine."

il = (9E0.2) 245.6 = 1146.3 .611 216 .-£11.1)

il = 1146.5 o. - £45.6 - g8.24>j.
920.2